An employee monitors foil-wrapped Cadbury Creme Eggs as they move along the production line at the Bournville Cadbury factory in Birmingham (File photo)

Redditors were particularly irked by changes to Cadbury Creme Eggs.

In 2015, it was revealed that Kraft had quietly changed the chocolate coated shell from Dairy Milk to a “standard cocoa mix chocolate," a change the firm says simply returned Creme Eggs to their original formula.

Mondelez says that it has not changed the forumla of its iconic Dairy Milk product, and that it reverted to the Creme Egg's 1971 chocolate recipe after six years of using Dairy Milk.

Defending its investment in the UK, the firm said in a statement: "Since 2010, Mondelez has invested over £200 million in manufacturing and R&D in the UK and we are working hard to ensure the future of British manufacturing is inspiring and competitive for generations to come.

"We have also located, in the UK, the global headquarters for chocolate invention."

But a new documentary set to air on Monday will expose the changes to Cadbury's in the six years since its takeover.

'Dispatches: Secrets of Cadbury' will "lift the lid on what’s been happening to one of our favourite brands."